America's Most Vulnerable Places: Diablo Canyon Power Plant

In 2008, an undersea fault line was discovered a half mile from this 18,000-gigawatt nuclear plant, which supplies electricity to more than 1.6 million homes. "They need tests to confirm the plant's ability to withstand earthquakes," Bea says. But seismic testing would displace marine mammals and kill fish larvae, and local agencies have so far blocked them. "There are diagnostic tests that are not environmentally invasive," Bea says. "Our one real option is not to ignore the problem."